Due to environmental concerns, there is a pressing need to eliminate the use of disposable spin-on filters of the type typically utilized in vehicular applications. The environmental issue arises with respect to the residual oil left in these filters when they are replaced. The volume of residual oil left in a conventional spin-on filter used with a vehicle engine may be as much as a quart. Since these filters currently are disposed of in landfills, the amount of residual oil in any one landfill can be significant enough to cause serious environmental concerns. For example, presently it is estimated that each year in Minnesota alone about 250,000 gallons of oil goes to the landfills as a result of the disposal of oil filters. It is anticipated that the European Community will ban spin-on filters in the near future. Hence, there exists a need to develop alternative oil filtration systems that eliminates the environmental concern raised by the residual oil left in spin-on type filters.
Energy and vehicle weight concerns have also resulted in the increased usage of engines of reduced displacement operating at increased revolutions per minute. In such engines, more heat is rejected to the lubricating oil than in larger, slower running engines, and this has increased the usage of oil coolers with such engines.
One particularly desirable type of oil cooler is a so-called "donut" oil cooler. Donut oil coolers are compact and may be readily installed at the location on the engine whereat a conventional spin-on filter would be located. The spin-on filter is then mounted directly on the donut oil filter.
Needless to say, however, such an arrangement perpetuates the environmental degradation that has accompanied the use of spin-on filters. Thus, there is a real need for an oil cooling and filtering system that retains the many advantages associated with the use of donut oil coolers and yet overcomes the environmental problems that come with the use of spin-on filters.